Known in the UV tanning field is use of lamps enclosing an inert gas in a transparent bulb and having two electrodes at the bulb ends to submit the gas to an electric potential difference. By connecting the lamp to the domestic supply mains, the gas contained in the bulb and submitted to the potential difference imposed by the electrodes is activated and emits luminous and thermal power. This electric connection is obtained by providing an attachment terminal at one bulb end, which terminal has two projecting metal plugs of the standard type, of cylindrical shape, each of them being electrically connected to a respective electrode of the lamp. The two plugs can be coupled to a respective outlet of a tanning reflector by a known outlet-plug coupling.
The gas enclosed in the bulb generally comprises an inert gas and metallic halides giving the gas specific brilliancy and conductivity properties when said gas is passed through by electric current.
A very high electric potential difference (in the order of some thousands of volts) is required by these lamps, on switching on, which difference is necessary to overcome the insulating characteristics of the inert gas enclosed in the bulb and to create a current passage through the gas. While this potential difference is applied for a short period of time as required for generating an electric discharge through the gas, it causes electric overloads and in particular overcurrents tending to damage the plugs both in terms of melting of the plugs themselves due to said overcurrents, and in terms of electric discharges between the two plugs following the initial overvoltage imparted thereto.
It will recognised in fact that when the two plugs form an attachment of the known outlet-plug type, they are mutually spaced apart by an amount that is often insufficient to avoid occurrence of electric discharges between the plugs themselves on switching on of the lamp. This fact is also linked to the continuous technological evolution of the lamps that are planned in such a manner that they can operate at increasingly heavier operating parameters, such as power, voltage, current and temperature, while the geometry of the attachment and plugs has remained substantially unchanged over time.